Birth defects are common, costly, and deadly. They affect approximately 3% of all births, and they are associated with huge personal and financial costs. They are the number one cause of infant mortality, accounting for 20% of infant deaths in the U.S. Improvements in the care of infants with birth defects can reduce their associated morbidity and mortality. Evidence suggests that racial/ethnic and socioeconomic disparities exist in the care and survival of infants with birth defects, although in general little attention has ben directed toward their investigation, much less their elimination. Most studies have focused on racial- ethnic disparities in survival. It is also important to investigate disparities in care and morbidity among infants with birth defects. Care and morbidity are important proximal determinants of infant survival, as well as long- term health. Very few studies have examined such disparities among infants born with birth defects. Rigorous examination of disparities in care, morbidity and survival among infants with birth defects is a critical gap in the field of infnt health that needs to be filled. Improved understanding of these disparities will enable the development of translational efforts to eliminate them, and thus improve infant survival and health, and pediatric well-being. Our proposal will address this research gap by examining racial-ethnic and socioeconomic disparities in the care, morbidity and mortality of infants born with birth defects. In this population-scale analysis we will examine disparities in the contributin of birth defects to infant mortality in a huge underlying study population of more than 3 million births, which includes >75,000 infants with birth defects. This inquiry will provide a robust understanding of disparities in the contribution of birth defects to overall infant mortality in th entire birth population - a major public health contribution in and of itself - as well as disparites in cause-specific mortality, among infants born with birth defects. Among infants with birth defects, we will also examine how care and morbidity are influenced by race-ethnicity and SEP. Care and morbidity will be characterized by a diverse set of variables, e.g., quality of care variables such as level of care of delivery hospital and morbidity-related factors such as hospital re-admissions, timing of surgery and length of stay. We propose to investigate our aims within a diverse study population of approximately three million births that occurred in California from 1995-2010, which includes approximately 75,000 babies born with birth defects, actively ascertained by the California Birth Defects Monitoring Program. We will link this information with vital records (birth certificates and infant and fetal death certificates) and hospital discharge data, both of which are derived from state-wide programs, to amass a comprehensive dataset that will enable us to answer our specific aims. Ultimately, our investigation will identify sub-groups of the population and health care- related structural factors that could be targeted for heightened surveillance, intervention or change, in order to improve the survival and health of babies born with birth defects.